A Princess of Mars: Edgar Rice Burroughs

I know this is a classic, so maybe I missed something...something huge. I thought this book was awful, the only thing it had going for it was that it was short. There were a few things that didn't make sense, but I got to the point where I didn't care anymore. A lot of the frustration came from the writing. The author would have the characters talk about something and give answers, but yet the idea didn't exist on Mars... so how could then have talked about something they have no knowledge of. There was also a scene where the hero helps a Martian, who is 10 feet tall and has more gravitational pull out of a window... he would have been smashed to smithereens. The story is about a man who is being chased by Native Americans and hides in a cave, somehow the cave transports him to Mars where he falls in love with a beautiful Martian who resembles a human, he fights for her, she is kidnapped, he frees her, they fall in love, he dies and comes back to earth never seeing his Martian baby.